RIO DE JANEIRO—Until recently, it seemed as if the worst of the coronavirus pandemic was finally over in Manaus, a city of more than 2 million people in the middle of the Brazilian Amazon. As the number of COVID-19 cases slowed in June, authorities dismantled field hospitals. Bars and river beaches reopened soon after, drawing crowds of people out of isolation. In September, children went back to school, packing into cramped classrooms.
Just a few months earlier, the city was the epicenter of Brazil’s coronavirus outbreak. At the peak of the crisis, patients with COVID-19 in Manaus died at four times the national mortality rate. Public hospitals overflowed, and city workers dug mass graves. By September, the coronavirus had infected 66 percent of people, leading researchers to question whether Manaus was the first city in the world to reach herd immunity.
